The present invention relates to a releasable binding for a gliding board, comprising a part secured to a boot and a part intended to be fixed on a gliding board, in which the part intended to be fixed to the gliding board comprises a pair of jaws which can be moved apart from one another and an elastic means opposing this movement apart, and in which the jaws and the part secured to the boot are designed so as to make it possible for the jaws to be moved apart, by the part secured to the boot when the boot is being fitted in the binding and upon release and to hold the boot on the gliding board after the boot has been fitted.
Such a binding is known from Patent FR 2 409 064. In this binding, the sole of the boot is fitted with a plate retained between the two jaws of the binding, the lateral sides of this plate having a hollow cutout in order to provide longitudinal holding of the boot. Each of these jaws is mounted at the end of an arm capable of pivoting about a vertical axis.
Bindings of the same type are described in Patents U.S. Pat. No. 4,143,886 and U.S. Pat. No. 5,799,966, the contents of which are incorporated by reference. These bindings also include a pair of jaws and are characterized by the presence of rods for transmitting the forces from the spring to the jaws articulated about a vertical axis.
Still further, U.S. Pat. No. 3,647,235, the content of which is incorporated herein by reference, and French Patent 2553671 describe such an invention. However, in both cases, it is necessary that both bindings swivel in order to insert a boot
Some of the prior art bindings have the advantage, on the one hand, of responding well to a twisting movement of the leg because of their position in the central part of the boot and, on the other, of being capable of being used for boots of different lengths without the need for adjustment. In such bindings, it is certainly easy to ensure good lateral gripping of the sole of the boot or of the metal plate fixed to this sole, by the jaws. However, the same is not true as regards the holding of the boot along a determined axis of the gliding board. This is because, even though the shape of the jaws is perfectly matched to the shape of the plate of the boot the spring which holds the jaws would need to be excessively powerful in order to prevent any rotational movement about a vertical axis. Further, wear on the jaws and the plate of the boot increases the possibility of rotation, which, even if very limited, equates to play for the user, which play makes control of the gliding board inaccurate and creates a feeling of insecurity. A similar play also appears when the skier presses on the rear of the boot.
Keeping the idea of retaining the boot by a pair of jaws which are located in the central region of the sole of the boot, what is needed is an in invention which avoids the drawbacks of the bindings according to the prior art, that is to say to produce a binding with lateral jaws which provide improved holding of the boot in its longitudinal direction.
A binding is provided wherein the boot is reed by a pair of jaws which are located in the central region of the sole of the boot, in which the binding has lateral jaws providing improved holding of the boot in its longitudinal direction.
The binding further comprises additional holding means, retained elastically, opposing at least a twisting movement about an at least approximately vertical axis of the part secured to the boot these additional means being preferably located in front of the jaws, relative to the heel of the boot.
Hence, even in the presence of angular play of the boot in the jaws, the additional holding of this boot neutralizes this angular play.
As explained above, the angular play is produced both dug slight twisting movements and because of wear.
The additional holding means could also retain the boot against wrenching, that is to say like conventional toe pieces.
The additional holding means preferably consist of a jaw articulated by a swivel joint and of a slide held bearing against the lower part of said jaw by said elastic means, so as to hold the jaw elastically in a determined position.
The swivel joint allows the jaw to pivot in all directions in the space above the binding. The boot can hence come out of the jaw both in the event of twisting and in the event of falling forward or backwards.
According to a preferred embodiment of the invention, the elastic means retaining the jaw pair is mounted between the pair of jaws and the jaw of the additional holding means, so as simultaneously to provide retention of the jaw of the additional holding means.
A binding of this type is therefore no builder than the bindings according to the prior art. The elastic means is covered by the sole of the boot and extends over a length substantially shorter than the length of the boot.
The jaws of the pair of jaws are in the form of a lever of the first class whose axis is parallel to the longitudinal axis of the binding, and they bear on a horizontally and axially sliding V-shaped cam retained by the elastic means.
The common elastic means, mounted between the V-shaped cam and the slide on which the jaw of the additional holding means bears, consists, for example, of one or two springs working in compression or of at least one leaf working in buckling mode.